Contrivance for setting impelling members to zero, particularly in connection with taxicabs



June 16, 1964 S. H. WALLQVIST CONTRIVANCE FOR SETTING IMPELLING MEMBERS TO ZERO, PARTICULARLY IN CONNECTION WITH TAXICABS Filed Oct. 16, 1961 United States Patent CONTRIVANCE FOR SETTING IMPELLING MEM- BERS TO ZERO, PARTICULARLY [N CONNEC- TION WITH TAXICABS I Sven H. Wallqvist, Halmstad, Sweden, assignor to Halde Aktiebolag, Halmstad, Sweden, a corporation of Sweden Filed Oct. 16, 1961, Ser. No. 145,363 Claims priority, application Sweden Oct. 17, 1960 1 Claim. (Cl. 235-47) In most of the present day taximeter types a cam disk is adapted to control the feeding of digits in the debiting indicator. This contrivance generally consists of a pivoted arm bearing with spring-pressure on the periphery of the cam disk. When the cam disk is rotated, said arm will be slowly raised in order then to fall rapidly down to the bottom of a notch in the curve. The falling motion of the cam releases the feeding of the debiting indicator. It is essential that the road distance from the beginning of the drive to the first item debited and between the following consecutive items be kept exact on the values determined by the tariff in consideration. In modern taximeters one would therefore pass from the previously used numerously divided cam disks to cam disks having a single notch so as to eliminate unavoidable division errors. It is just as important, also, that in commencing the drive the cam disk always starts from exactly the same position, so that the length of road covered up to the first debit always becomes constant. In the zerosetting of the cam disk the latter is called upon to take its proper starting position as rapidly as possible without oscillations or loss of time, so as to eliminate any possibility on the part of the taxidriver by a quick manipulation of the taximeter to start driving from a more advantageous starting position on the cam disk than the intended one. In this connection it is necessary that the mass of the cam disk and the masses unavoidably connected therewith are as small as possible.

In previously known constructions of zeroizing means for the cam disk one would either lift a wheel in the train of wheels out of engagement and would force the cam disk in its direction of rotation ahead toward a stop, or, one would solely force the cam disk, without breaking the train of wheels, toward a stop (with utilization of the one-way coupling always provided on the axle of the cam disk). In this compulsory rotation of the cam disk the tooth play in the feeding series of teeth will be taken up from a wrong direction. This involves that a varying portion of the first length of road is used for setting the train or series of teeth, before the cam disk commences to turn. The present invention has for its object to avoid said drawbacks.

A contrivance according to the invention is principally distinguished by the feature that the impelling member and a preferably heart-shaped zeroizing cam disk are arranged on a hub, which is rotatably mounted, preferably on the axle driving the impelling member, said hub being adapted to be disengaged from the driving axle, while the impelling member is zeroized through cooperation with a wheel, a sliding shoe or the like arranged on a swingably mounted arm in the frame and the zeroizing cam disk, so that the impelling member is turned to zeroizing position. The device for disengaging the impelling member is constituted by a friction coupling, the one couplingv half being rigidly connected with the impelling member and the axle carrying the heart-shaped cam disk, whereas the other coupling half is non-rotatably connected with an axle coupled to the driving means.

The invention will be described more closely with reference to the annexed drawing, which represents a 3,137,442 Patented June 16, 1964 perspective view of a form of embodiment of the invention.

The contrivance shown consists of a gear wheel 1 which is in connection with the entering drive. This Wheel is connected to a further gear wheel 2, which is rigidly connected with an axle 3. The intermediate portion 4 of the axle 3 is of a square configuration to bring about a nonrotatable connection to the one coupling half 5 of a friction coupling. Said coupling half 5 is formed as a casing surrounding the coupling. An annular friction coating 6 is arranged on the inside wall of said casing. Said coating is intended to cooperate with the other coupling half 7 in the form of a disk, which is rigidly connected to a hub 8, which is rotatably mounted on an extension of the axle 3. The hub 8 has arranged thereon a heartshaped zeroizing cam disk 9 as well as an impelling member in the form of a cam disk 10. Both of said cam disks may be adjusted and locked relatively to one another in definite mutual positions by means of a nut 11 provided on a screw 12 threaded into the end of the hub 8. To bring about the requisite coupling friction in the coupling 5, 6, 7 a multi-legged leaf spring 13 is adapted to act upon the other side wall of the coupling half 5, that is to say on the side wall not provided with any friction coating, in a direction such that the friction coating 6 is brought into engagement with the outer edge of the coupling half 7. To effect disengagement between the coupling halves, balls 14 are arranged in holes in a support 15 underneath the coupling half 5. Said balls are adapted to cooperate with a pane 16 arranged underneath the supporting plate 15 and swingably mounted on the axle 3. The pane 16 is provided with recesses 17, in which the balls are intended to rest, when the coupling takes its thrown-in position. By a turning movement of the pane 16 the balls 14 are forced up out of their recesses 17 and are pressed to bear on the outside of the coupling half 5, the latter being then displaced along the square portion 4 of the axle against the action of the leaf spring 13, whereby the two coupling halves are brought out of engagement with one another. For the turning of the pane 16 the latter is provided with a spring-actuated arm 16'. The figure shows the position of the contrivance when the balls 14 have just been pressed up out of their recesses 17 by the pane 16.

Through the friction coupling as now constructed, the hub 8 with the zeroizing cam disk 9 and the impelling cam disk 10 is freely rotatable on the appertaining portion of the axle 3. Zeroizing may then be readily effected. The zeroizing is carried out by means of a rotatably mounted arm 18, which is provided with a wheel 19 on the one free end thereof. The arm 18 is adapted to be swung by means of a cam disk 20, which is arranged on a zeroizing axle 21. The wheel 19 is thus caused to cooperate with the heart-shaped zeroizing cam disk 9 and makes the latter to turn, until the wheel comes to rest in the curve recess of the zeroizing cam disk. Arranged on the zeroizing axle 21 is a further cam disk 22 cooperating with the end of the arm 16 to disengage the coupling half 7 and the parts united therewith.

When in the arrangement shown the zeroizing axle 21 is turned in the direction shown by the arrow 23, an actuation of the arm 16' will first take place to bring about said disengagement, whereupon the cam disk 20 will cooperate with the arm 18 to swing the latter to cooperation with the cam disk 9 in the manner described for zeroizing. When thrown into position for operation the turning movement of the axle 21 is continued, the arm 16' coming thus out of engagement with the cam disk 22, whereby the coupling is thrown in. The wheel 19 is then still in contact with the cam disk 9. Upon a continued turning movement of the axle 21 to the position for throwing in the drive, the arm 18 is brought out of en- 3 gagernent with said further cam disk 20 and returns to its initial position through spring-actuation. The contrivance is now prepared to be turned through rotation of the gear wheel 1.

In a construction of the zeroizing system according to the invention, only the last link in the mechanical train of drive will be released, that is to say, the impelling member, the zeroizing cam disk and the appertaining coupling half, as stated. Owing to the small masses zeroizing of the impelling member can be efiected very swiftly. The impelling member is locked all the time in its predetermined initial position through the zeroizing arrangement and remains therein as far as to the commencement of driving. The impelling member starts its movement from exactly the proper initial position and the same initial position for every drive already begun, the impelling member being then driven by a set train of gear wheels.

What is claimed is:

In a taximeter, an axle, a hub rotatably mounted on said axle, a first cam disc movably mounted on said hub, a heart-shaped zeroizing cam movably mounted on said hub in spaced relation to said first cam disc, said first cam disc and heart-shaped zeroizing cam movable relative to each other and adapted to be adjustably fixed in selected positions, said axle and hub each having mounted thereon cooperating halves of a drive coupling through which rotary movement of said axle can be transmitted to said hub, spring means to normally urge said coupling halves into engagement with each other, a support adjacent said coupling, said support having portions defining a plurality of openings therein in alignment with said coupling, ball members movably disposed in the openings in said support, a pane movably mounted on said axle on the side of the support opposite said coupling and having recesses in which said ball members are adapted to be supported, a zeroizing axle rotatably mounted in said support in spaced relation to said first-named axle, a second cam disc fixed to said zeroizing axle and engageable upon rotation thereof to engage a portion of said pane to efiect movement of the same to move said ball members into engagement with said coupling whereby the halves thereof are disengaged, an arm movably mounted on said support and having one end disposed adjacent said zeroizing axle, a wheel mounted on the opposite end of said arm, a third cam disc mounted on said zeroizing axle and engageable with said cam to cause movement thereof toward said hub whereby said wheel engages said heart-shaped zeroizing cam to cause rotation of the same and said hub when said coupling halves are disengaged to effect zeroizing of the taximeter.

References Cited in the file of this patent UNITED STATES PATENTS 1,160,137 Browne Nov. 16, 1915 2,563,668 Abel Aug. 7, 1951 2,637,492 Winch May 5, 1955 FOREIGN PATENTS 616,980 Great Britain Jan. 31, 1949 

